From: Aubrey Li <aubrey.li@linux.intel.com>
To: tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org,
hpa@zytor.com
Cc: ak@linux.intel.com, tim.c.chen@linux.intel.com,
dave.hansen@intel.com, arjan@linux.intel.com,
adobriyan@gmail.com, akpm@linux-foundation.org,
aubrey.li@intel.com, linux-api@vger.kernel.org,
linux-kernel@vger.kernel.org,
Aubrey Li <aubrey.li@linux.intel.com>
Subject: [PATCH v14 3/3] Documentation/filesystems/proc.txt: add AVX512_elapsed_ms
Date: Wed, 10 Apr 2019 09:53:25 +0800 [thread overview]
Message-ID: <20190410015326.24500-3-aubrey.li@linux.intel.com> (raw)
In-Reply-To: <20190410015326.24500-1-aubrey.li@linux.intel.com>
Added AVX512_elapsed_ms in /proc/<pid>/status. Report it
in Documentation/filesystems/proc.txt
Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Linux API <linux-api@vger.kernel.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
Documentation/filesystems/proc.txt | 29 ++++++++++++++++++++++++++++-
1 file changed, 28 insertions(+), 1 deletion(-)
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 66cad5c86171..c4a9e48681ad 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -207,6 +207,7 @@ read the file /proc/PID/status:
Speculation_Store_Bypass: thread vulnerable
voluntary_ctxt_switches: 0
nonvoluntary_ctxt_switches: 1
+ AVX512_elapsed_ms: 8
This shows you nearly the same information you would get if you viewed it with
the ps command. In fact, ps uses the proc file system to obtain its
@@ -224,7 +225,7 @@ asynchronous manner and the value may not be very precise. To see a precise
snapshot of a moment, you can see /proc/<pid>/smaps file and scan page table.
It's slow but very precise.
-Table 1-2: Contents of the status files (as of 4.19)
+Table 1-2: Contents of the status files (as of 5.1)
..............................................................................
Field Content
Name filename of the executable
@@ -289,6 +290,32 @@ Table 1-2: Contents of the status files (as of 4.19)
Mems_allowed_list Same as previous, but in "list format"
voluntary_ctxt_switches number of voluntary context switches
nonvoluntary_ctxt_switches number of non voluntary context switches
+ AVX512_elapsed_ms time elapsed since last AVX512 usage recorded
+
+ AVX512_elapsed_ms:
+ ------------------
+ If AVX512 is supported on the machine, this entry shows the milliseconds
+ elapsed since the last time AVX512 usage was recorded. The recording
+ happens on a best effort basis when a task is scheduled out. This means
+ that the value depends on two factors:
+
+ 1) The time which the task spent on the CPU without being scheduled
+ out. With CPU isolation and a single runnable task this can take
+ several seconds.
+
+ 2) The time since the task was scheduled out last. Depending on the
+ reason for being scheduled out (time slice exhausted, syscall ...)
+ this can be arbitrary long time.
+
+ As a consequence the value cannot be considered precise and authoritative
+ information. The application which uses this information has to be aware
+ of the overall scenario on the system in order to determine whether a
+ task is a real AVX512 user or not.
+
+ A special value of '-1' indicates that no AVX512 usage was recorded, thus
+ the task is unlikely an AVX512 user, but depends on the workload and the
+ scheduling scenario, it also could be a false negative mentioned above.
+
..............................................................................
Table 1-3: Contents of the statm files (as of 2.6.8-rc3)
--
2.21.0
next prev parent reply other threads:[~2019-04-10 1:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-10 1:53 [PATCH v14 1/3] /proc/pid/status: Add support for architecture specific output Aubrey Li
2019-04-10 1:53 ` [PATCH v14 2/3] x86,/proc/pid/status: Add AVX-512 usage elapsed time Aubrey Li
2019-04-10 1:53 ` Aubrey Li [this message]
2019-04-10 1:58 ` [PATCH v14 1/3] /proc/pid/status: Add support for architecture specific output Andy Lutomirski
2019-04-10 2:20 ` Li, Aubrey
2019-04-10 2:25 ` Andy Lutomirski
2019-04-10 2:36 ` Li, Aubrey
2019-04-10 3:39 ` Li, Aubrey
2019-04-10 14:54 ` Andy Lutomirski
2019-04-11 1:02 ` Li, Aubrey
2019-04-12 0:55 ` Li, Aubrey
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